How to decrease HPA expent for Talon valve? The answer!
On the one of the best airgun forum in the web – guns.ru – once was a discussion about WERY big expent of HPA per shot on talon. And decision was found!
There http://www.sendspace.com/file/o6kzc0 is archve of that discussion.
Can somebody try to repeat?
If something is not understand – ask questions, I’ll try to explain.
Best regards – Gennady
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Hi Ewoodie,
Muzzle report is about equal to my normal valve turned down to 250m/s. Both are very low! I would be interested how high the report would be at 280m/s?
Cheers,
marc
How about the muzzle report / sound/ blast / music*
For me it is music, the sound of a Talon / Stealth 😛 ( incl. the ping )
Hey Ewoodie,
Did a little work today! Made a tophat for the 5.5mm barrel (my 6.35mm barrel is thicker). Got a pretty consistent 250m/s. Not very encouraging.
You managed to get a nice string with a normal valve!
cheers,
Marc
hey Marc did you find time to work on the valve?
Did look today with WW, and find the other thing about it very interesting,
it make less noise 🙂
Next thing is to make, a other valve and an O ring in the valvehouse ( nut.)
but at the moment also 2 other bottle projects fastflow/ better string .
hi,
did give more hammerforce with a brass spacer, little more power, but still NOT a lot of good shots.
Start with a fill of 190 Bar after 50 shots say +/- 160 Bar, that’s a good point.
See the purple line.
Hey Wimone,
Slipstick isn’t the biggest problem. I’ve kept the static tophat as small as possible to reduce contact with the o-ring and it seals perfectly. But this design prooves to me the airforce design relies heavily on the backpressure on the valve to open it! That’s probably why you don’t get much of an upward powercurve and valvelock is very sudden above a certain pressure.
Got my toolbits today. Very nice lookingcarbide tools! Sandvik quality!
Ordered one for bigger grooves also. You never know when it comes in handy!
I’m afraid with the design you describe things will get complicated to keep concentric straight and afghanistan proove.
Cheers,
Marc
aha,
is this working? just a rough sketch. Wimone
Hi,
upload you pictures to http://www.photobucket.com
and insert the link : IMG code.
By using Molycote 33 medium it’s very slippery the breech.
I’m still having problems with the fact that the bolt/breech has to move over stil standing barrel and new valve housing type.
Orings have a high slipstick effect. So to get them moving needs a lot of energie from the hamer and when moving the valve back on its seat also takes (i think) to much time and so to much air is lost.
So I was thinking in by passing the bolt/breech with 3 thin steel pins who connects the hamer to valve. Bolt/breech can be static then and the valve could close very vast?
regards wimone
(p.s how do I attach a picture?)
Now we must BOTH increase the hammer force, to get on the normal power level.
That bring the next Q. to me, with more hammerforce the valve stay longer open to get the wanted power.
With a normal tophead the valve is longer open becauce the pressure works also on the tophead, but when the pellet start, the force is gone.
When we give the hammer more force ( for the pelletspeed we want ) it stay, even when the pellet is gone.
I don’t know If it will work. 🙁 to get more shots.
Hey Ewoodie,
Got mine finished today no o-ring yet but leaks are very minor. Will cut an aditional o-ring groove once the tool comes in!
Got the same results as you did ewoodie, powerdrop with old bottle from 275m/s to 195m/s in new bottle! All shots with .25JSB’s. Did test at 100/140 and 170 bars. Made little difference. So there should be potential for a lot of shots at consistent speed!
Just goes to show how dependand the airforce design is on that backpressure on the valve. Probably also the cause why it’s so easy to get loads of power from this setup!
Have to sleep over this for a night or two!
Cheers,
Marc
did finish the valve with the 4 mm valvestem at the end and with the 4 mm O-ring inside.
one thing, the power drop to 20 ft/pe 😕
a lot of shots but I’m NOT interested in pelletspeed of 230 m/s
( 754 ft/sec ), so I need more hammer force.
But I try this om my workhorse, and I don’t mess with it.
So first I put an other rifle together to play, and try more hammer force.
here a pic. of the data
Did make a very smal O-ring cutter from a big one, with the Dremel tool with cutting disk.
with my magnifying glass on my head, it was not a big deal in brass.
( O-ring 4 x 1 mm )
He Ewoodie,
Shure seems like it. And to be honest, I’m glad I made it till this stage. This valve is a whole lot of work. I hope it lives up to it’s promisses!
But always good to get some excercise in dialing in parts within 0.01mm!
Cheers,
Marc
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Did a little shotstring with the normal valves.
.22 .25 . 25
261,9 256,5 251,5
277,5 267,2 275,5
284,3 263,6 272,8
274,9 261,7 283,8
288,6 269,4 289,6
285,9 272,3 291,7
289,5 271,9 290,1
287 272,8 289,2
288,5 271 288,1
289,7 272,2 288,6
288,4 270,3 289,1
286,2 271 287,8
287,1 271,3 288,5
288,2 270,5 288,4
288,1 269,8 286,9
288,8 269,2 287,4
286,6 269,4 288,3
289,4 269,4 287,5
288,4 268,3 286,9
288 269,1 286
288 269,2 285,7
287,7 267,3 284,8
287,5 268,7 284,1
286,3 266,7 282,6
285,9 265,5 283,9
286,3 265,5 282,2
285,5 264,7 283,1
284,3 266,1 282,5
285,1 265,7 281,7
284,4 263,4 279,9
283,3 264,4 280,2
283,4 262,4 278,9
282 261 278
281,4 262,4 277,3
281,3 261,3 275,1
281,8 259,5 276,2
280,7 259 276
278,8 260,2 273,1
279,9 258,1 272,1
280,3 257,1 273,2
279,5 256,1 271,2
279,8 256,5 270,7
279 254,3 120bar
277,6 110bar
277,4
275,5
276,1
277,4
275,1
274,9
274,4
275,1
274
273,7
125bar
First .25 had a transfer port of 3.1mm 2nd of 3,4mm
I’m happy.
The new valve isn’t living up to it’s expectations. Shoots way too slow. At those speed I could get a 100 shots with my normal valve!
Cheers,
Marc